Accompanying semiconductor process miniaturization, there is a tendency for current consumed by semiconductor devices to increase. Therefore, in order to reduce the consumption current of a semiconductor device, technology is being used to reduce voltage supplied to internal circuitry of the semiconductor device by using a voltage regulator. Until output voltage of the voltage regulator settles into a prescribed voltage range, the internal circuitry cannot operate normally, and it is necessary to wait until the internal circuitry reaches the prescribed voltage range. Accordingly, speeding up of time for activating the voltage regulator is desired.
Patent Document 1 discloses a voltage regulator for speeding up time for activating. This voltage regulator is provided with a reference voltage circuit, an error amplifier, and an output transistor wherein a field-effect transistor is source-follower connected, and wherein a gate of the output transistor is connected to output of the error amplifier, and a pre-charge circuit is connected to a gate of the output transistor. Here, a phase correction capacitor is connected to the gate of the output transistor, and the pre-charge circuit pre-charges the phase correction capacitor by a transistor that is ON when power is turned on. Therefore, when power is turned on, output of the voltage regulator increases instantaneously.
[Patent Document 1]
    JP Patent Kokai Publication No. JP-A-5-127763